[yifuyang]

Maybe on my experiens,I learn the system design by think about how to build the system or software in our life ,just like how to build a Uber or an Amazon. If you feel like it's a little hard to do, just try some simple things like a lift or a parking.

As you said ,you have a lot of small apps, mabey you could do something to link them together, and build a middle layer service for all the apps. In this progress, you should consider all the part of designing a distrubuted system, it could help you a lot, I guess.

Perhaps it's not the best way to improve the ablity for system design, it works a lot on me at least.